Amphibian plane



n 9, 1930. D. w. DOUGLAS 1,78 ,184

AMPHIBIAN PLANE Filed April 23, 1927 3 Sheets-Sheet 1 17/ E/EYVTOJFDaMuo 14 144: Douaufld QTTO/PNE'K Dec. 9, 1930. D. w. DOUGLAS AMPHIBIANPLANE Filed April 23, 1927 3 Sheets-Sheet 3 '7? YTOPNEX Patented Dec. 9,1930 UNITED STATES- PATENT OFFICE DONALD WILLS DOUGLAS, 01' SANTAMONICA, CALIFORNIA, ASSIGNOB, BY MESNE A s- SIGNIEN'I'S, TO DOUGLASAIRCRAFT COMPANY, INC., OI LOS ANGELES,

A conroaarrou or DELAWARE CALIFORNIA,

' AMPHIBIAN PLANE Application filed April 23, 1927. Serial No. 188,008.

My invention relates to airplanes. In the development of navalfacilities, carrier-ships have been'brought into use which carryairplanes and serve as a take-off and landing place for these airplanes;At present the airplanes carried by the carrier-ships are land-planes,being provided with wheels as landing-gear. There is a certain degree ofdanger connected with the flying of a landplane over the water in viewof the fact that such a plane cannot land on the water. In view of thisdanger the airplanes are confined within a limited area around thecarrier-ship.

It is an object of this invention to provide an airplane which may beconverted from a land-plane into a seaplane. My invention is very usefulin connection carrier-ships since, when the airplane leaves thecarrier-ship, it may be converted into seaplane so that in case ofnecessity it may land upon the water without danger of sinking.

A further object of this invention is to provide an airplane of thischaracter in which the converting mechanism may be easily operated.

A still further object of this invention is to provide an airplane ofthe character mentioned in which the wheels or the pontoon are properlypositioned with respect to the center of gravity of the airplane.

Another object is to provide in an airplane of the above class a waterlanding-gear and a land landing-gear which are connected by a novelmechanism for automatically moving one of the landing-gears intoalighting position when the other landing-gear is in retracted position.

Other objects and advantages of the invention will be made evidenthereinafter.

Referring to the drawings:

Fig. 1 is a perspective view showing an airplane of my invention withthe pontoon in alighting position and the wheels in retracted Fig. 5 isa front view of Fig. 3 partly sectioned to show the mechanism for movingthe pontoon from and into alighting position.

Fig. 6 is a front elevation of Fig. 4.

Fig. 7 is a side view partly sectioned showing the mechanism for movingthe pontoon and wheels into and from alighting position.

Fig. 8 is a perspective view showing the mechanism for moving thepontoon and wheels into and from alighting position.

Referring to the drawings and particularly Figs. 1 to 4, the airplanehas a fuselage 11, airfoils 12, a rudder 13, an elevator 14, a tail-skid15, and a propeller and motor 16. The parts just mentioned may be of anydesirable design which is not important to this invention. These partsjust enumerated will be referred to inthe appended claims as the mainstructure of the airplane.

Referringparticularly to Figs. 5, 7 and 8, pontoon-carriers 18 arepivotally connected to the lower part of the fuselage 11 and are adaptedto extend downward therefrom. These pontoon-carriers are arranged inpairs as shown and may swing from the position shown in Figs. 1, 3, 5,7, and 8 into positions shown in Figs. 2, 4. and 6. Provided below thefuselage 11 is a pontoon 19 which is the water landing-gear of theinvention. The pontoon 19 has the lower ends of the pontoon-carriers 18pivotally secured thereto. The pontoon 19 is adapted to swing from analighting position, as illustrated in Figs. 1, 3, 5, 7, and 8, into-aretracted position against thei fuselage 11, as illustrated in Figs. 2,4, an 6.

Mechanism for moving'the pontoon be tween these positions is illustratedbest in Figs. 5, 7, and 8. Pivoted at 21 to the upper part of thepontoon 19 between the rear pontoon-carriers 18 is an arm 22. This arm22 extends through a narrow opening 23 (Fig. 7) to the interior of thefuselage 11. Mounted inside the fuselage 11 is a pair of verticallead-screws 24 which are supported by bearings 25, these bearings 25being secured to a seamless-tubin frame 26 of the fuselage 11. The upperen of the arm 22 is pivoted at 28 to a nut 29 having portions whichsurround the lead-screws 24. The two leadvided with a pair of sprocketwheels 34. Extended around one of the sprocket wheels screws 24 aredrivably connected together at their upper ends b gears 29 so that therotate in opposite irections. The lea screws 24 are, therefore, providedwith right and left-hand threads and so arethe oitions of the nut 29. Atthe upper end 0 one of the lead-screws 24 is a beveled gear 30 which isengaged b a beveled gear 31 mounted on a drive sha extends horizontally.and an end thereof adjacent to the side 0 the fuselage 11 is pro- 34 isa front sprocket chain 35 which extends around a front sprocket 36,which front sprocket 36 is rovided with an o erating crank 37. As iustrated in Fi 7 t e front sprocket 36 is placed in a pi ots cockit 39of the fuselage and may be operated by t 0 pilot of the airplane.Extended around the other of the s rockets 34 is a rear sprocket server.

chain 40' which extends around a rear sprocket 41 havin' an 0- cratingcrank 42. As illustrated in 1g. 7 t e rear sprocket 41 is situated inan'observers cock-pit 44 of the airplane and may be operated by the ob-It will be seen that by revolving either of the cranks 37 or 42, thelead-screws 24 may be moved so as to raise or lower the.

up or end of the arm 22. When the upper end of the arm 22 is raised, thepontoon 19 is moved from aliihting position throu a osition indicateddotted lines 45 of 1g. 7 into retracted-posi ion; and when the upper endof the arm 22 is lowered, the pontoon will be returned to alightingposition.

Pivotally connected to the pontoon 19 on opposite sides thereof areframes 48 WhlOh carry wheels 49 which are the land landin gear referredto in the appended claims. 0 s shown in the various views of the drawinthe pontoon 19 has shafts 50 connected to t e opposite sides thereof andextending parallel to thedirection of flight of the an lane. The frames48 each have an axle-mem r 52 and a strut-member 53. The axle-membersare pivoted to the rear ends of the shafts 50, and the strut-members 53are ivoted to the front ends of these shafts 50. e outer ends of thestrut-members and 'axle members of the se arate frames 48 are securedtogether as indlcated at 55. The axle-members 52 are curved near theircentral part so that outer 32. The drive shaft 32 shown'in Figs. 2, 4and 6 of the therefore desirable was. mama shock ,nected to the "pontoonby the frames 48 and to the main structure by the thrust-members 58 thatthey are automatically moved into retracted position when the pontoon'ismoved into alighting position; and they are auto. matically moved intoalighting position when the ontoon is moved into retracted position. 0illustrate the manner in wh1ch this takes place, let us first refer toFigs. 1,

.3 and 5 in which the pontoonis'shown in alighting position and thewheels are shown in retracted position. At this time the frames 48 areextending diagonally upward and the.

thrust-members 58 are extending in substantially' a horizontal plane. Asthe pontoon is moved into retracted position the entire. main frames 48and the wheels 49 move in a horizontal direction or in a directionsubstantially parallel to the line of flight a distance equal to thehorizontal movement of the pontoon 19. As the frames 48 move rearwardwith the pontoon, the inner ends thereof which are secured to thepontoon are moved upward a distance equal to the upward movement of thepontoon. The outer ends of the frames 48, however, are moved downward.When the frames 48 are moved rearward, the outer ends thereof must swingaround the pointsof attachment of the thrust-members 58 to the rigidarms 59. The thrust-members 58, as Wlll be obvious from an inspection ofthe drawings, cause the outer ends of the frames 48 to move downward adistance substantially equal to the length of the thrustmembers and intoalighting When the pontoon 19 is moved in the reverse direction or intoalightin position, it is moved not only downward, ut also in a directionparallel to the axis of the shaft 50.

This increases the distance between the shafts 50 and the universaljoints 60 and is equivalent to elon ting one side of atriangle formed byt e shaft 50, the pivot 55 and the universal joint 60, with the resultthat the pivot 55 attempts to assume a position intermediate the shaft50 and universal joint 60. Since the universal joint 60 is positionedabove the shaft 50, the pivot 55 moves to a position below the universaljoint .60 and above the pivot 55, thus moving the wheels 49 above thepontoon 19. T

It will be noted that when the pontoon is moved into alighting positionit is extended forward from the fuselage so that the front end thereofextends below the propeller of the airplane. This is done so that thepontoon will occupy a proper position with respect to the center ofgravity of the airplane and so that the pontoon may properly support theairplane on the surface of the wedposition as rawings.

ter. 'The wheels 49 are so positioned that they also occupy a proper pane when they are in alightmg position.

. ter without danger to the fliers.

A very important feature, and the essence of the invention, is themechanism by which the water landing-gear or the pontoon may be movedinto and from alighting' osition and the land landing-gear or the w eelssimultaneously moved into and from retracted position.

The mechanism is designed so that it ma be operated either by the serverwith equal facllit In the foregoing description I have shown but asingle embodiment of the invention. It should be understood that variousmodifications may be made without departing from the s irit and scope ofthe invention and that different designs may be produced under theprinciple of this invention. I intend the claims appended hereto to bebroad enough to cover entirely the invention as shown in the drawingsand all designs and modifications in which the principle of theinvention may be embodied.

I claim as my invention:

pilot or the ob- 1. In an airplane the combination of: a'

main structure; a water landing-gear movable-relative to said mainstructure; a land landing-gear movable relative to said main structure,said land and said water landinggears being relatively movable; andmeans for moving said water landing-gear into alighting position andsaid land landing-gear from alighting position and vice versa.

2. A combination as defined in claim 1 in which said land landing-gearis attached to and is moved into and from alighting position by saidwater landing-gear.

3. A combination as defined in claim 17 in which said means for .movingsaid water landing-gear comprises: an arm connected to said waterlanding-gear; a lead-screw for operating said arm; and means foroperating said lead-screw.

4. In an airplane adapted to alight and arise from either land or waterthe combination of: a main structure, a water landinggear carried bysaid main structure; a land landing-gear connected to said mainstructure; means for moving said Water landing-gear from retracted intoalighting position, and means operatively connecting said waterlanding-gear and said land landinggear in a manner to move said landlandinggear completely above the surface of said water as said waterlanding-gear is advanced into alighting position.

5. In an airplane the combination of: a

position with re'-' s ect to'the center of gravit with the airmainstructure; a waterlanding-gear adapted to-move be'tween'alightingposition and retracted "osition; means for moving said water lan in-gear from alighting posit ion land landing-gear to said main structureand cooperating-with said frame structures to move said landlanding-gear to alighting position when said water landing-gear is movedto retracted position and woe versa.

6. In an airplane the combination of: a. y main structure; a waterlanding-gear movably carried by said main structure; a land landing-gearcarried by said water landing gear and movable relative thereto; strutsconnecting said land landing-gear and said main structure, said strutsguiding said land land'- ing-gear from'retracted position into alightingposition as said water landing-gear is moved from alighting positioninto retracted position. i

7. A combination as defined in claim 6 in which said struts includeshock absorbers.

8. A combination as defined in claim 6 in which said land landing-gearis pivoted to said water landing-gear.

9. A combination as defined in claim 6 in a portion of a landland'ingear said waterlanding-gear on an axis substan-- tially parallelto the direction of flight of said airplane.

10. A combination as defined in claim 6 in which said struts are securedto arms extending from the fuselage of said airplane.

11. In an amphibian airplane the combination of: a main structureincluding a fuselage; pontoon carriers pivoted to said fuselage; apontoon pivoted to said pontoon carriers; means for controlling theposition of said pontoon relative to said fuselage; frames on eitherside of said pontoon; wheels carried by said frames; and meansconnecting said frames and said fuselage for extending said wheels inalighting position when said pontoon is moved into a retracted position.

' 12. In an amphibian airplane the combination of: a main structureincluding a fuse lage; pontoon carriers pivoted to said fuselage; apontoon pivoted to said pontoon carriers; means for controlling theposition of said pontoon relative to said fuselage; frames pivoted oneither side of said pontoon wheels carried by said frames; and strutsconnecting said frames and said main structure whereby said wheels aremoved into alighting position as said pontoon is moved into a retractedposition.

13. In an amphibian airplane the combination of: a main structureincluding a fuselage; pontoon carriers pivoted to said fuselage wardandlage; a pontoon pivoted to said pontoon carriers; means forcontrolling the position of said pontoon relative to said fuselage;frames pivoted on eitherside of said pontoon; wheels carried by saidframes; arms extendm from said fuselage and struts connecting sai armsand said frames in a manner to swin saidwheels into. retracted positionwhen sai pontoon is moved into alightin'g position. and

vice versa. a a e 14. In an amphibian airplane, the combination of: afuselage; a water landingar movable toward and away from said usea landlanding-gear movable toaway from said fusela e and movable relative tosaid water lan ing-gear; and means for simultaneouslyraising said landlanding-gear and lowering said water landing-gear m a manner tending toprevent a vert cal movement of the center of gravity of said ai laneduring the relative movement'of said anding-gears.

15. In an amphibian airplane, the combi nation of: afuselage; a pontoonmovable downward and forward from said fuselage; a frame structurelongitudinally ivoted to each side of said-pontoon; whee s carriedstruts secured to said frame structure near said wheels; and means forsecuring said struts to said fuselage, said struts moving said wheelsand said frame structures into retracted tion as said pontoon is moveddownwar into alighting position.-

16. In an amphibian air'plane,-the combia wheel carried by said frame; astrut pivoted to said frame at a secondary point and pivoted to saidmain structure about a-tertiary point; and means for mov ng her inadirection such that the istance between -said primary point and saidtertiary point is increased and said secondary point is moved above saidprimary point.

19. In an amphibian. airplane, the combination of a mam structure; apontoon movable below said main structure; a frame piv oted 'at' aprimary oint to said pontoon; a wheel carried by said frame; a strutpivoted to said frame at a secondary oint and pit said mem- I oted tosaid main structure a out a tertiary 30 point; and means for moving saidpontoon m a direction such that the distance between said prima pointand said tertiary point is increase and said secondary point is movedabove said primary point.

In testimon whereof, I ave hereunto set my hand at os Angeles,California, this 15th da of AKILI, 1927.

. DON D WILLS DOUGLAS.

said frame structure; shock-absorbing nation of: a mam structure; awater landinggear movable downward and forward from a retracted positionadjacent said main structure to an alightin position; a landlanding-gear movable "tween ali htin "position and retracted pjosition,sai lan landing-gear being mov' 1e relative to said water landing-gear;and means operated by the movement of said water landing-gear to movesaid land landin -gear to retraoted positionwhen said water ending-gearmoves to ali hting position, and vice versa.

17. an amphibian airplane, the combination of: a main structure; a waterlandmg-gear carriedbv said main structure and movable relative thereto;means for movin said water landing-gear between retracted and ahghtingpositlons; a landlanding-gear connected to said main-structureandmovable between retracted and alighting positlons; and 'lmkage meansconnecting said a water landing-gear and said land landinggear for movrnsaid land landing-gear into ahghtmg position when said water landinggear1s moved to retracted position, and vice 18. In an airplane, thecombination of: a inam structure; a member movable below said mamstructure; a frame pivotally secured at a primarypointto said member;

